NBC NEWS – It’s no surprise that people say racist things on Twitter, especially with so many high-profile cases involving celebrities and famous athletes. But just how many tweets a day contain something racially insensitive?

About 10,000, according to U.K.-based think tank Demos. It used a filter to analyze 126,975 English-language tweets and then estimated that one in every 15,000 tweets contained a “racist or ethnic slur.”

Of those, anywhere between 47.5 percent and 70 percent were “non-derogatory” or used to “express in-group solidarity.” (Cutting out the term “white boy” reduced the total number of racially insensitive tweets in half).

That still leaves the tricky question of how many tweets would be considered, by most people, as racist. A program can’t parse the racist subtext of a tweet and human analysts have different ideas of what counts as racism.